Oregon defensive lineman Arik Armstead will forgo his senior season and enter the NFL draft, the school announced Tuesday afternoon, one day after the Ducks lost the College Football Playoff National Championship to Ohio State.

As a former five-star recruit who received his first college scholarship offer at age 14 from UCLA, Armstead’s late commitment to Oregon was one of its biggest recruiting coups ever. Because of that, he played under massive expectations in Eugene that accompanied his 6-foot-8, 290-pound frame. He dabbled in basketball at Oregon, played 13 games as a true freshman on the gridiron and became a full-time starter in his junior season at defensive end in UO’s 3-4 scheme.

“After three years preparing with my teammates and coaches, I feel I’m ready to test myself at the next level,” Armstead said in a release from the school. “All the support I’ve received from Coach (Don) Pellum and Coach (Ron) Aiken, the rest of the Oregon coaches and staff and in my academics has prepared me to make this jump.”

Neither Armstead, nor his family, could be reached for comment Tuesday evening.

He is the first domino of potential early entrants to fall for Oregon after a 13-2 season.

The most anticipated announcement is that of Heisman Trophy-winning quarterback Marcus Mariota, considered a top-five pick if he chooses to turn pro. Fellow juniors Byron Marshall, a 1,000-yard running back in 2013 and the team’s leading receiver this season, and defensive lineman DeForest Buckner are also considering the NFL draft ahead of Thursday’s deadline for underclassmen to file paperwork to apply for the draft and give up their remaining collegiate eligibility.

Armstead intends to return to school and earn his general social science degree, the school said.

He is the 67th underclassman to declare so far and the seventh defensive end, joining players such as Florida State’s Mario Edwards Jr. and Nebraska’s Randy Gregory, considered the top end in the 2015 class.

The 6-foot-8, 290-pound Armstead struggled with injuries throughout his career, particularly a broken wrist as a sophomore, which limited his effectiveness — he recorded a combined 41 tackles his first two seasons — if they didn’t knock him out of any games prior to 2014.

As a junior, Armstead missed games against UCLA and California due to an ankle injury, yet his production flourished in a starting role. He finished with a career-high 46 tackles this season, 10th-most on the team, and his six quarterback hits were a team-high.

“We appreciate Arik’s contributions to the program over the last three years and wish him well at the next level,” second-year head coach Mark Helfrich said in the statement.

In October, one NFL talent evaluator told The Oregonian/Oregonlive that Armstead was viewed as a work-in-progress player with “upper-echelon ability” because of his mix of size and footwork — honed working with his father, Guss, a longtime basketball trainer in the Sacramento area where he grew up.

“You don’t build guys like that too often,” the NFL employee said. “He’s a monster of a dude. What I saw in the first couple games is he’s putting it all together with his ability and football savvy. He’s being disruptive, getting upfield and shedding blocks. I think a lot of 3-4 teams would fall in love with him because he’s strong, and at the same time, he is a good athlete. As far as a run stopper and a big disruptive guy, that’s what you want.”

NFLDraftScout.com projects Armstead as the sixth-best at his position and between a first- or second-round pick in May’s draft, which will be held in Chicago.

His Oregon finale ended on a bittersweet note. Despite a career-high nine tackles and recovering a fumble by OSU quarterback Cardale Jones, Armstead and the defense couldn’t stop Buckeye running back Ezekiel Elliott from setting a new championship record with 246 rushing yards during a 42-20 loss to the Buckeyes on Monday evening in Arlington, Texas.